November 13, 2013

Obesity Surgery Linked To Higher Risk Pregnancy

Scientists writing in the journal BMJ say women who have had an obesity surgery are at an increased risk during pregnancy.

In 2008, nearly half a billion people were classified as obese around the world. The health condition is believed to result in a two to four year reduction in life span, and eight to ten years for those who are morbidly obese. Bariatric surgery is considered to be one of the most effective methods to help reduce weight to improve health.

Researchers from the Karolinska Institute in Sweden found women with a history of bariatric surgery are at increased risk of giving birth to a preterm or small-for-gestational age babies.

The team conducted a population-based study to evaluate the association between bariatric surgery and perinatal outcomes between 1992 and 2009. They used data from the Swedish Medical Birth Register, the National Patient Register and the Education Register and compared women who had undergone bariatric surgery and had a child with mothers who did not undergo the surgery.

Women with a history of bariatric surgery were older, more often obese, had lower education and were more often smokers. After matching numbers with the control group, the team was left with 2,534 post-bariatric surgery births compared with 12,468 control births of similar age, parity, early pregnancy BMI, smoking status, education level and delivery year.

The team found infants of women with bariatric surgery history had lower average weights at delivery. They said 5.2 percent of them were small for gestational age and were at least two standard deviations below the normal, as opposed to only 3.0 percent in the control group.

Researchers also discovered only 4.2 percent of the babies of mothers with bariatric surgery history were large for their gestational age, compared to 7.3 percent of the control group.

"Mothers with the same BMI gave birth to babies of varying weights depending on whether or not they had undergone bariatric surgery, so there is some kind of association between the two," said Dr. Olof Stephansson, obstetrician and Associate Professor at the Clinical Epidemiology Unit at Karolinska Institute, said in a press release. "The mechanism behind how surgery influences fetal growth we don't yet know, but we do know that people who have bariatric surgery are at increased risk of micronutrient deficiencies."

The team said they believe women with bariatric surgery history should be considered a risk group when pregnant, meaning they should have an extra ultrasound to check fetal growth or be given special dietary supplement recommendations. They also said bariatric surgery has numerous benefits for mothers, such as lowering the risk of diabetes, cardiovascular disease, cancer and stroke.